python初级 1 数据类型和变量

Posted 2020-10-20 永远的麦田

一、整数(int)

例：  0 1 2 3 -1 -2 –3

In [31]: print(type(0))
<class ‘int‘>
In [32]: print(type(1))
<class ‘int‘>
In [33]: print(type(2))
<class ‘int‘>
In [34]: print(type(3))
<class ‘int‘>
In [35]: print(type(-1))
<class ‘int‘>
In [36]: print(type(-2))
<class ‘int‘>
In [37]: print(type(-3))
<class ‘int‘>

二、浮点数（小数）(float)

例：0.0 0.3  15.5 1.0 –1.45

In [39]: print(type(0.0))
<class ‘float‘>
In [40]: print(type(0.3))
<class ‘float‘>
In [41]: print(type(15.6))
<class ‘float‘>
In [42]: print(type(1.0))
<class ‘float‘>
In [43]: print(type(-1.45))
<class ‘float‘>

 

三、字符串(str)

指的是””或是’’里面的内容

例：‘2a‘ "33" "ab\‘cd"

In [44]: print(type(‘2a‘))
<class ‘str‘>
In [45]: print(type("33"))
<class ‘str‘>
In [46]: print(type("ab\‘cd"))
<class ‘str‘>
In [48]: print("2a")
2a
In [49]: print("33")
33
In [50]: print("ab\‘cd")
ab‘cd

如果想表示’或是”时,需要采用转义符\, 如果需要表示\时,在外面加上转义符

例:"I\‘m a boy"  "say \"hello world\""  "print \\"

In [51]: print("I\‘m a boy")
I‘m a boy
In [52]: print("say \"hello world\"")
say "hello world"
In [53]: print("print \\")
print \

 

四、布尔值(bool)

例：True, False

In [56]: print(type(True))
<class ‘bool‘>
In [57]: print(type(False))
<class ‘bool‘>

 

五、空值(NoneType)

例：None

In [58]: print(type(None))
<class ‘NoneType‘>

 

 

 

练习

请打印出以下变量的值：

n = 123

f = 456.789

s1 = ‘Hello, world‘

s2 = ‘Hello, \‘Adam\‘‘

s3 = r‘Hello, "Bart"‘

s4 = r‘‘‘Hello, Lisa!‘‘‘